SIMVASTATIN-SODIUM DELAYS CELL-DEATH OF ANOXIC CARDIOMYOCYTES BY INHIBITION OF THE NA+/CA2+ EXCHANGER

When incubated under anoxic conditions, cultured neonatal cardiomyocytes undergo cell necrosis. Simvastatin-sodium, the bioactive metabolite of simvastatin (a potent serum cholesterol-lowering drug), delayed the anoxia-induced myocyte necrosis in a dose-dependent manner. This beneficial effect of simvastatin-sodium could not be attributed to its cholesterol-lowering properties. We found that simvastatin-sodium, at concentrations of 20 and 50 mu M, attenuated the rise in intracellular Ca2+ concentration ([Ca2+](i)) measured with Fura-2 in anoxic cardiomyocytes. In a test of sarcolemmal Na+/Ca2+ exchange activity, simvastatin-sodium attenuated the rise of[Ca2+](i) upon incubation in sodium-free buffer, which normally causes a reversal of Na+/Ca2+ exchange and cellular calcium overload. The inhibitory action of simvastatin-sodium on the sarcolemmal Na+/Ca2+ exchanger could well explain the cardioprotective effect of the drug on myocytes subjected to anoxia.